Many types of flush mounted, slant surface gates and barricades have been designed to control traffic flow either into or out of a controlled area such as at rail and highway intersections, bridges, or parking lots. These prior art designs incorporate complex electrical or mechanical control systems for the controlled or automatic raising and lowering of a gate or barrier plate, for example, as shown in U.S. Pat. Nos. 2,327,366; 2,741,859 and 3,748,782. Typical prior art electrical control systems are activated by tickets, dispensors, coin machines, or credit card type machines. They are designed to provide limited control of vehicular movement in one or both directions. Other typical prior art mechanical control systems cause the barrier plate to move up or down in response to a vehicle moving over the barrier plate in the desired direction and prevented movement of vehicles in the opposite or undesired direction.
Prior art flush mounted barrier plate designs often require excavation below the surface of the ground for placement of control components, such as springs, bearings, linkage or hydraulic or electro-mechanical elements to move the barrier plate. Prior art systems are not easily adapted to vehicular entrances to buildings where the locations of basements, snow-melting cables, and water-proofing or other structural considerations preclude excavation. Also, prior art barricades and barrier plates presented a slant surface at the approximate wheel elevation of a vehicle. Such an arrangement would not damage an approaching vehicle when the vehicle contacts the slant surface. Other prior art barricades have been of slight construction or not flush mounted as in U.S. Pat. No. 1,460,200. Such barricades provide limited protection against persons who might seek forced access to a sensitive area.
It is therefore an object of this invention to provide a surface mounted, protective gate or barricade designed to deny access of vehicles to an area. Another object of this invention is to provide a barrier plate which, when raised, prevents forced access by vehicles from one direction. A further object of the invention is to permit free passage of vehicles from either direction when the barrier plate is in a lowered position. An additional object of the invention is to provide a barricade capable of withstanding heavy impact. It is a further advantage of the present invention to provide a simplified surface mounted apparatus, comprising minimal moving parts, which can be manufactured, installed and maintained with comparative ease.
A further object of the present invention is to provide a design with inherent flexibility permitting a change in the barrier plate angle and height of the barrier plate edge from the roadway so that there would be only limited damage to a vehicle contacting the barrier plate.
A further object of this invention is to provide simplified installation of a powered barricade.
It is a further object of this invention to provide pillars adjacent to the barrier plate which cooperate with the barrier plate when raised to add greater structural integrity to the barricade.
Other objects of this invention will appear from the following description and appended claims.